The report showed only one race had shifted in favour of the Republicans -- Arizona’s 1st district, from "likely Democrat" to "leaning Democrat".

The Cook Report supports a CNN poll released today, which also indicates a Democrat advantage.

CNN shows the dems ahead in the House of Representatives 55 to 42 per cent. Seven in Ten likely voters said they wanted to send a message to Donald Trump.

Camera IconPresident Donald Trump arrives for a rally at Allen County War Memorial Coliseum.Picture: AP

The president, unimpressed with CNN’s predictions, slammed the network in a tweet saying:

"So funny to see the CNN Fake Suppression Polls and false rhetoric. Watch for real results Tuesday. We are lucky CNN’s ratings are so low."

The president is in fighting mode today, ahead of tomorrow’s midterms -- which have become a battle for the soul of a turbulent country.

His outspoken tweets so far today have targeted illegal voting -- threatening massive penalties for anyone who attempts to fudge the system.

With stops in Cleveland, Ohio; Fort Wayne, Indiana; then Cape Girardeau, Missouri today, it will be well after midnight (local time) before the real estate billionaire and populist showman gets back to the White House.

After that the president will only have a few hours more before polls open across the world’s largest economy.

"Everything we have created and achieved is at stake on election day," Mr Trump told a cheering crowd in Cleveland, as he kicked off his furious last round of campaigning today.

"If the radical Democrats take power, they will take a wrecking ball to our economy and to our future."

Donald Trump is not on the ballot in the midterms, in which the entire House of Representatives and a third of the Senate are up for grabs.

All 435 seats in the US House are up for re-election. And 35 Senate seats are in play, as are almost 40 governorships and the balance of power in virtually every state legislature.

But in a hard-driving series of rallies around the country, Mr Trump, the most polarising US president in decades has put himself at the centre of every issue.

With a characteristic mix of folksiness, bombast and sometimes cruel humour, he says voters must choose between his stewardship of a booming economy and what he claims would be the Democrats’ extreme-left policies.

The bid to make it all about Trump is a gamble, as is his growing shift from touting economic successes to bitter -- critics say racist -- claims that the country is under attack from illegal immigration.

In the run-up to vote Mr Trump has sent thousands of soldiers to the Mexican border, suggested that illegal immigrants who throw stones should be shot, and told Americans that the Democrats would turn the country into a crime-and-drugs black hole.

"They want to impose socialism on our country. And they want to erase America’s borders," Trump told a raucous rally in Chattanooga, Tennessee late Sunday.

That worked for Trump in his own shock 2016 election victory. But the angry tone has turned off swathes of Americans, giving Democrats confidence that they could capture at least the lower house of Congress, even if the Republicans are forecast to hold on to the Senate.

The Democrats rolled out their biggest gun in the final days of the campaign: former president Barack Obama, who made a last-ditch appeal for an endangered Senate Democrat in Indiana.

Laying into the tangled legal scandals enveloping the Trump administration -- especially the possible collusion between his presidential campaign and Russian operatives -- Mr Obama scoffed: "They’ve racked up enough indictments to fill a football team."

And describing the election as even more consequential than his own historic 2008 victory as the first non-white president, Mr Obama said more than politics is at stake.

"The character of our country’s on the ballot. One election won’t eliminate racism, sexism or homophobia," Mr Obama said. "But it’ll be a start."

The party of a first-term president tends to lose congressional seats in his first midterm.

But a healthy economy favours the incumbent, so Mr Trump may yet defy the historical pattern.

Although polls generally agree on Democrats winning the House and Republicans retaining the Senate, the margins are fine and a few key races will determine whether a real upset is on the cards.